Sincere question: where are you buying beef for $5/lb? I shop at Costco and ground beef is close to $10/lb
Beef on craiglist (1/4, 1/2 or whole) is averaging $6-12/lb for mostly grass fed beef raised <50 miles from me.
If I want to get $5/lb ground beef, I have to stick to 73/27 rolls, and they have to be 5lb or larger.
I have started seeing beef/pork mixes for $4/lb, but alas, those are not to my taste.
In oz I have only seen this kind of packaging for pet food or lunch meat (colloquially 80/20 in this case would probably refer to the meat to sawdust ratio).
Otherwise prices in Australia are similar but for beef mince from the supermarket meat counter.